Evaluation of reservoir flooding by 2 MHz and 60 MHz electromagnetic wave logging data

Abstract

Electromagnetic wave logging data provide two aspects of phase difference and amplitude ratio information, which can comprehensively reflect the changes of formation conductivity and dielectric constant. According to the characteristic that the dielectric constant is basically independent of the salinity of formation water and only related to the water content, through the phase difference of 60MHz reflects the water saturation at a certain water content or porosity of the flush zone, the phase resistivity log of 2MHz reflects the oil-bearing property of the unfractured formation and determines the fluid properties or water flooding degree through the radial comparison of different detection depth curves. Based on the analysis of actual well data, the response of electromagnetic wave logging to water flooding degree of pure sandstone reservoir above 0.4 m is more obvious than that of conventional resistivity logging. The reservoirs with heavy argillaceous and calcium and small bed thickness must be corrected before the evaluation of water flooding layer of thin and poor oil reservoir can be applied.